1. Field of the Invention
The present invention relates to a displayer and a pixel circuit thereof. More particularly, the present invention relates to a displayer and a pixel circuit thereof, in which two pixel electrodes belongs to a same pixel type and be disposed adjacent to each other.
2. Descriptions of the Related Art
As liquid crystal displayers (LCDs) are continuously developing towards large-sized ones, continuous progress also needs to be made in wide viewing angle technologies of LCD panels in order to overcome the problem about the viewing angle with large-sized displayers. Currently, multi-domain vertical alignment (MVA) LCD panels and polymer stabilized alignment (PSA) LCD panels are among the wide viewing angle technologies that are commonly used.
To improve the color shift in the LCD panels, a kind of advanced-MVA LCD panel has been proposed. In the advanced-MVA LCD panel, each of pixels is divided into a main display region (i.e., a main-pixel) and a sub-display region (i.e., a sub-pixel); and through a proper circuit design and a proper driving method, the main-pixel and the sub-pixel in the same pixel are provided with different voltages respectively to improve the color shift. Accordingly, designs in which a single pixel region has two data lines and one scan line (also referred to as a gate line) or in which a single pixel region has one data line and two scan lines are introduced, which are called as the 2G1D structure and the 2D1G structure respectively. Taking the 2D1G structure as an example, a pixel region comprises two sub-pixels, which are controlled by different data lines respectively.
Furthermore, referring to FIG. 1, a schematic view of a pixel circuit is shown therein. Generally speaking, there are two kinds of different electrical connection structures between the aforesaid MVA LCD and the data lines, i.e., positive (P) pixel electrodes and negative (N) pixel electrodes. The two kinds of pixel electrodes are staggered in the pixel circuit in a PNPNPN or NPNPNP pattern. However, this staggered pattern is prone to cause color shift in an image generated by the pixel circuit when a specific frame is displayed, thus degrading the displaying quality of the LCD.
Specifically, among pixel electrodes in FIG. 1, R represents a red pixel electrode, G represents a green pixel electrode, B represents a blue pixel electrode, a white background represents that the corresponding pixel displays a bright state, and a black background represents that the corresponding pixel displays a dark state. As can be known from FIG. 1, when a frame is displayed and the R pixel electrodes, the G pixel electrodes and the B pixel electrodes are all in the bright state or all in the dark state simultaneously, the color shift phenomenon will occur. Taking the arrangement of the pixel electrodes in FIG. 1 as an example, when a frame of a checkerboard pattern is displayed, the green main-pixels in the main-pixel rows A, B, C are all positive.
In detail, referring to FIG. 2, there is shown a schematic view depicting that a common electrode signal is pulled away from an original direct current (DC) level by a data line signal with the positive and negative polarities. When the data line signal (Vdata) has a transient, the common electrode voltage (VCOM) at the pixel array side is pulled by Vdata to result in the waveform as shown in FIG. 2. When the potential of the data line signal rises, the VCOM will be raised; otherwise, when the potential of the data line signal falls, the VCOM will be dropped. Therefore, when the data lines are driven in the column inversion manner, in one main-pixel rows A, B, C, the green main-pixels are all of the positive polarity and the red main-pixels and the blue main-pixels are all of the negative polarity. Thereby, the VCOM signal is pulled towards the polarity direction of the red (or blue) main-pixels. Therefore, in the frame displayed, the green color has a gray scale higher than the originally defined level while the other two colors have gray scales lower than the originally defined levels. This causes the aforesaid color shift (bias to the green color) phenomenon. Furthermore, when arrangement of the pixels of different colors in the pixel electrodes are altered, different color shift phenomena will be caused.
Accordingly, an urgent need exists in the art to effectively prevent occurrence of the color shift phenomenon in an image generated by the pixel circuit so as to improve the displaying quality of the LCD and increase the added value of this industry.